Wednesday, February 23, 2011

groundwater sampling

I decided I hadn't done any technical posts in a long-ass time...

One of the first things that a newbie in environmental consulting does is go out and sample groundwater monitoring wells. Doesn't matter if you're a biologist, geologist, engineer... most environmental investigations and practically all remedies involve groundwater monitoring, and the work doesn't involve a whole lot of technical know-how and has minimal chance for personal injury. That last bit, of course is relative to all fieldwork - any time you work outside, you have a decent chance of getting into some sort of vehicle incident, getting bitten by something, throwing your back out hoisting a cooler, and getting chased by angry property owners. But I digress.

I've sampled approximately...actually, I have no idea how many wells I've sampled. "Hundreds" is probably a low-ball estimate. I don't get much of a chance to sample wells any more - I usually do more complicated fieldwork when I do go into the field. But I've been helping someone out with groundwater sampling recently, and it reminded me of how complicated this stuff can actually be.

Sure, a field sampler is sent out with a work plan of some sort that states the sampling protocol, what bottles to fill, and where to send them. Those are usually straightforward. But what happens when things go wrong? The low-stress sampling procedure (which varies widely by jurisdiction) has some standards that you need to meet in order to get the sample correctly. How much can the water level in the well go down? What happens if you keep losing water? The water can be extracted by bailers (takes forever and is bound to get water everywhere) or by pumps (all finicky in their own special way), and what you use can affect sample quality.

I haven't seen or heard of companies that do really thorough training of new field people before they're sent on their own to do groundwater sampling. The older field hands often forget how many little details they've internalized or don't explain why each step is important (including filling all the paperwork out!) because there's always some sort of time crunch. And if the "why" isn't explained, then it looks like just a bunch of busywork and it's easy to blow off. Then you go into the field with someone who's been on their own for a while but not really trained (if you're lucky), or you get back strange data or a regulator or lawyer starts asking questions (if you're not so lucky) and find out exactly how much has gone missing.

Maybe I'm just too picky. Most sample results are never scrutinized by regulators or anybody else. But if you don't know what you're doing, you may get burned the few times it actually is really important. Which sample will be critical in litigation later? Who knows when you're out in the field, swatting mosquitos...